1. Field of the Invention
The present invention relates to a novel antibacterial polypeptide which is obtained from a body fluid of an insect and more particularly from flesh fly (Sarcophaga peregrina).
2. Related Arts
It has been known that a certain antibacterial substance will appear in a body fluid, when a vaccine is inoculated to an invertebrate such as insecta ["Eur. J. Biochem." Vol. 106, page 7 (1980)].
The present inventor has also found that the Sarcophaga peregrina produces a certain antibacterial polypeptide in its body fluid, when a larva of the insect is injured in its body wall. The polypeptide was isolated and purified and its physicochemical properties have been investigated [see Japanese Patent Publication Nos. 59-13730 (A) published Jan. 24, 1984 and 61-122299 (A) published Jun. 10, 1986].
Since the polypeptide induced in the insect shows a wide antibacterial spectrum and almost no toxicity, the substance has been expected to be an edible antibiotic. Its yield, however, is rather low.